chkconfig

The chkconfig command can also be used to activate and deactivate services. The chkconfig --listcommand displays a list of system services and whether they are started (on) or stopped (off) in runlevels 0-6. At the end of the list is a section for the services managed by xinetd.

If the chkconfig --list command is used to query a service managed by xinetd, it displays whether the xinetd service is enabled (on) or disabled (off). For example, the command chkconfig --list rsync returns the following output:

rsync          on

As shown, rsync is enabled as an xinetd service. If xinetd is running, rsync is enabled.

If you use chkconfig --list to query a service in /etc/rc.d, that service's settings for each runlevel are displayed. For example, the command chkconfig --list httpd returns the following output:

httpd         0:off   1:off   2:on    3:on    4:on    5:on    6:off

chkconfig can also be used to configure a service to be started (or not) in a specific runlevel. For example, to turn nscd off in runlevels 3, 4, and 5, use the following command:

chkconfig --level 345 nscd off

How to monitor only the last n lines of a log file?

It might suffice to use watch:

$ watch tail -n 15 mylogfile.txt

How to get the current date and time in the terminal

The command is date
To customise the output there are a myriad of options available, see date --help for a list.
For example, date '+%A %W %Y %X' gives Tuesday 34 2013 08:04:22 which is the name of the day of the week, the week number, the year and the time.

Octave for GNU/Linux

The recommended way for installing Octave and Octave-Forge packages on GNU/Linux systems is via each distribution package installation system.
More detailed instructions follow.

Contents

• 1 Debian and Debian-based (such as Ubuntu)
• 2 Fedora
• 3 Gentoo
• 4 Red Hat Enterprise/CentOS
• 5 SUSE Linux and openSUSE
• 6 Arch Linux

Debian and Debian-based (such as Ubuntu)

Main article: Octave for Debian systems

Simply install Octave from your distribution repository:

apt-get install octave

For old versions of Ubuntu that only supply old versions of Octave, consider using Octave's PPA. For more details, see the Debian specific instructions page.
There are also Debian packages for each of the Octave-Forge packages, usually named octave<pkgname>, e.g, octave-image and octave-statistics for the image processing and statistics package respectively. A complete list of them can be found with the command:

aptitude search ?description\(octave-forge\)

Fedora

Main article: Octave for Red Hat Linux systems

The packages can be installed using the dnf command, they are:

• octave
• octave-devel

octave-devel contains the octave headers and mkoctfile script and is really only needed by users who are developing code that is to be dynamically linked to octave. octave can be installed with the command:

   # dnf install octave

Gentoo

Octave is available through Gentoo's package management system, Portage:

   # emerge --sync

Add USE flag 'curl' into your /etc/portage/package.use file to enable remote Octave-Forge packages fetching

sci-mathematics/octave curl

and emerge Octave

   # emerge octave

Since Octave ver. > 3.4.0 is able to fetch Octave-Forge packages from remote repository, packages octave-forge or g-octave are no more needed.
Before installing any Octave-Forge package, in Octave command prompt you must type

pkg -forge list

and then install your favourite packages. Typically, you have to start with

pkg install -forge general

Red Hat Enterprise/CentOS

Main article: Octave for Red Hat Linux systems

Octave is available for Red Hat Enterprise Linux distributions through the EPEL repository. This section applies to CentOS, Scientific Linux, and other Red Hat Enterprise rebuild distributions as well.
Method 1 - the quick way:

   yum install epel-release
   yum install octave

Method 2 - if the above does not work:
First, follow these instructions to set up your system to install packages from EPEL. For example,

   # wget http://url/to/latest/epel-release-6-7.noarch.rpm
   # yum localinstall epel-release-6-7.noarch.rpm

Once the EPEL repository has been enabled, you can follow the rest of the instructions for Fedora to install Octave using yum.
Note that EPEL intentionally does not follow new releases as closely as other distributions. Consequently, the version of Octave provided by EPEL may be several months or years out of date. There are plans for the Octave maintainers to provide support and binary RPMs for enterprise GNU/Linux distributions; contact the maintainers mailing list for more information.

SUSE Linux and openSUSE

Main article: Octave for openSUSE

Binary packages for Octave are provided by all versions of openSUSE. It can be installed by command:

zypper in octave

Latest stable version of Octave and Octave-Forge are available on Science repository. For details see openSUSE specific wiki page.

Arch Linux

Main article: Octave for Arch Linux

Updated Octave's version is in the extra repository. It can be installed by typing:

   # pacman -S octave